Files provide a way for a VHDL design to communicate with the host environment
File declarations make a file available for use to a design
Files can be opened for reading and writing
- In VHDL87, files are opened and closed when their associated objects come into and out of scope
- In VHDL93 explicit FILE_OPEN() and FILE_CLOSE() procedures were added
The package STANDARD defines basic file I/O routines for VHDL types
The package TEXTIO defines more powerful routines handling I/O of text files
The VHDL file object is introduced above. Files may be opened in read or write mode, and once a file is opened, its contents may only be accessed sequentially. A detailed description of the use of file objects is beyond this module and will be discussed further in the 'Advanced Concepts in VHDL’ module.